1. Field of the Invention
The present invention relates to a suspended type transporting carriages such as an OHT (Overhead Hoist Transport) carriage, which is used in a manufacturing factory of a semiconductor device, an LCD (Liquid Crystal Display) device and the like and which travels on a track installed on or near the ceiling of the factory and transports the object, as well as a transporting system using such a carriage.
2. Description of the Related Art
In a manufacturing factory of a semiconductor device, an LCD device and the like, in order to deal with an increase of production amount, an improvement in production efficiency is strongly desired, as one of which it is desired to shorten the transporting time duration. In order to shorten the transporting time duration, it becomes an important point how to shorten the time duration required to transfer a carrier (i.e., a transported object) to a stocker or stacker device, which is a temporarily storage place for the carrier, from the carriage, how to shorten the time duration required to transfer the carrier to the carriage from the stocker, and so on. Here, the “carrier” or “transported object” in the present invention means a product, an intermediate product, a part, an article, a work, a partly-finished good, a good or the like (e.g, a semiconductor or LCD device), or means a box or container for containing such a product or the like (e.g, a container containing the semiconductor or LCD device), which has been transported or is to be transported by the transporting carriage.
For example, the semiconductor integrated circuit element, which is manufactured by the semiconductor manufacturing factory, is transported by the transporting system, while various processes such as thin film formation by CVD (Chemical Vapor Deposition), ion injection, photo-lithography, etching, inspection and so forth peculiar to the semiconductor manufacturing processes, are applied to the circuit element by various processing devices so that the final product is produced. In these processes, a plurality of semiconductor substrates are stored in a container, which is so called as a “FOUP (Front-Opening Unified Pod)” The semiconductor substrates in the container are transported between the processing devices by the transporting carriage, and are subjected to the respective peculiar processes by the respective processing devices. However, the processing time durations required for the respective processes are different between the processing devices. Thus, the waiting time duration until the next process is applied to the semiconductor substrates, whose duration or length is unknown, is normally generated for the semiconductor substrates. During this waiting time duration, by the transporting device, the FOUP containing the semiconductor substrates is once transported to, and is transferred (i.e., put) into a stocker or onto a simplified rack buffer from the carriage. When such a condition that the next process can be applied comes, the FOUP containing the semiconductor substrates is transferred (i.e., picked up) from the stocker or the simplified rack buffer to the carriage again, and is transported by the transporting system to the processing device for the next process. In case that the storage place for the FOUP is the simplified rack buffer disposed at the vicinity of the respective processing devices, the transferring operations (i.e., putting and/or picking-up operations) take a short time. On the other hand, in case that the storage place for the FOUP is the stocker which is disposed distant from the processing device, the putting and/or picking up operations take a long time. Therefore, to more often employ the simplified rack buffer instead of the stocker is effective for shortening the transporting time duration. By shorting the time duration required to put and/or pick up the FOUP, the improvement in the production efficiency is expected.
Japanese Patent Application Publication Laid Open No. 2005-150129 discloses such a simplified rack buffer disposed at the vicinity of the processing device. In this case, the transferring operations to and from the simplified rack buffer can be easily performed by a hoisting belt, which is disposed on the transporting carriage, and a sliding rack plate, which is slidable in a horizontal direction. The sliding rack plate allows the movement of the FOUP toward the transporting carriage.
Each of Japanese Patent Application Publication Laid Opens No. 2005-206371 and No. 2005-530361 discloses such a simplified rack buffer disposed at the vicinity of the processing device. In this case, the sliding rack plate is not used. Instead, the hoisting mechanism itself is slidable by virtue of the sliding mechanism. The hoisting mechanism is slid between the position right underneath the traveling rail and the lateral position of the traveling rail, so that the transporting carriage can directly access the port, which is lateral from the position right underneath the traveling rail.